Herb. No. 013 · Hypericaceae
European and West Asian meadows; now a roadside plant across temperate North America.
Native · Europe · West Asia
Native Also grown
LegalCautionplant
St. John's wort
Hypericum perforatum
Sunshine-yellow roadside herb for low mood — famous, effective in mild cases, and a notorious interactor.
The tiny translucent dots in the leaf are oil glands; crushed buds bleed a red pigment (hypericin). Standardized extracts have evidence for mild-to-moderate depression comparable to some SSRIs. Hyperforin induces CYP3A4 and P-glycoprotein, collapsing levels of many medicines including oral contraceptives and transplant drugs.
Flavor
Astringent green, then a red-oil balsam. Fresh buds stain purple.
Parts used
Flowering tops
Helpful
- Real evidence in mild depression
- Superb red oil for bruises and nerve twinges
Cautions
- Renders many prescriptions unreliable, including the pill
- Can trigger mania in bipolar disorder
- Phototoxicity at high dose